I think they are talking about children under 13. They can go in the tsa precheck line with an adult who has precheck even if the children's boarding passes don't say it. We have taken our grandkids with us through the line many times.
Yes re: kids. But the adult they are accompanying still has to have PreCheck on their boarding pass. Just having a card that gives you the PreCheck privilege (Global Entry, SENTRI, NEXUS, and the TSA PreCheck program) without the boarding pass notation does not let a person use the PreCheck line.
SW